• Question: Is glass a liquid?

    Asked by blatantlyninja to James, Marcus, Martin, Rob, Suzanne on 19 Mar 2012.
    • Photo: Marcus Gallagher-Jones

      Marcus Gallagher-Jones answered on 19 Mar 2012:

      No it is a solid. It’s in fact an amorphous compound of silicon dioxide (sand). You can make glass ou of other things also and when you go into material chemistry the real definition gets a little difficult.

    • Photo: Robert Thompson

      Robert Thompson answered on 19 Mar 2012:

      I think the idea of glass being a liquid is fueled by some debate . A quick straw pole of the scientists in my office shows that its not amazingly well known.

    • Photo: Suzanne McEndoo

      Suzanne McEndoo answered on 19 Mar 2012:

      I think glass has some funny properties, but it’s ultimately a solid. There are actually quite a bit of different types of matter beyond solid, liquid or gas. There’s also plasma, bose-einstein condensate, fermi condensate… Depending on where you draw the lines, there can be others too. And there will always be something that doesn’t quite fit well into any categories.

    • Photo: Martin Zaltz Austwick

      Martin Zaltz Austwick answered on 19 Mar 2012:

      Glass is like a liquid because the molecules in it are very random and disordered. Solids are usually more ordered. But it’s hard to think glass is much like water (apart from being transparent). But then a tomato is a fruit, apparently.

Comments

  • Photo: blatantlyninja

    blatantlyninja commented on :

    Thanks for all your answers!

    Marcus- what other compounds can you make glass out of? Are you refering to the various oxides that contribute to the colour, or can you have glass where the main constituent is not silicon dioxide?

    Robert and Suzanne- interesting, thanks

    Martin- why is glass so disordered when other solids are not? Is it to do with how it is made?

    The reson why I asked this question is because i heard somewhere that over a very very long time, the glass in a window (of a cathedral or something) can flow so that the pane is thicker at the bottom than the top… Isthis a complete myth?

  • Photo: Marcus

    Marcus commented on :

    Hi Blatantlyninja. Good question and it depends on how you define a glass. As martin mentioned part of the confusion over glass is that the molecules are organised randomly rather than in an ordered crystalline like structure. Basically any other solid where this is the case can be called a glass. To that end some plastics such as acrylic can be considered a glass. Another example are Chalcogenides which are the major substance in CD’s. They are derived from elements in the same period as sulpher, remember elements in the same period tend to have similar properties.